The Pathology/Animal Core will provide the Program Project uniform processing and staining of cells and tissues of microscopy. The Core will offer expert immunohistochemistry on light and transmission electron microscopy (EM) from the 4 Projects. More importantly, it will provide an experienced pathologist in the field of inflammation and repair, who can compare and integrate the pathological findings in all of the models. Most of the immunopathological methods employed are common to all of the projects so that a Core laboratory will provide uniform methods and interpretation. The central processing of tissue will result in cost savings, quality control and comparability between the results of the projects. The continual review of all of the histological findings by a single pathologist will ensure that both common and unique aspects of pathological results from different projects are appreciated immediately. The Animal portion of the Core will provide preparation and surgery for the intact animal models of myocardial ischemia/reperfusion used in Projects 1, 3, and 4. These models will include acute and/or chronic studies in mice, rats, and dogs. Each model has been chosen for a specific scientific purpose and will be supervised by a physiologists who had previous experience with each.